Refrigeration systems and refrigerants used therewith



p 24, 1958 R. c. SCHLICHTIG 3,402,570

REFRIGERATION SYSTEMS AND REFRIGERANTS USED THEREWITH Filed Dec. 23,1966 5 Sheets-Sheet 1 Q' HH mmmmeif E APOFATOE HEAT Xt'f/ANGFE 5:5 I yINVENTOR- FAtP/l 6. yam/(W276 ATTORNEY M P 1968 R. c. SCHLICHTIGREFRIGERATION SYSTEMS AND REFRIGERANTS USED THEREWITH 5 SheetS -Sheet 2Filed Dec. 23, 1966 IIOOO WWW NORMAL 50/! //V6 POI/V75 $8 mwskmwwq wM04; renew/v Pz/ w E Se t. 24, 1968 R. c. SCHLICHTIG I 3,402,570

REFRIGERATION SYSTEMS AND REFRIGERANTS USED THEREWITH Filed Dec. 23, 1966 T s Sheets-Sheet s Urv itt d, Stat s P te 'Ofice Patented Sept. 24,1968 $402,570 REFRIGERATION SYSTEMS AND REFRIGERANTS USED THEREWITHRalph CiSchlichtig, 11212 3rd 5., :,:.Seattle',-Wa sh. 98168 1Continuation-in-part of application Ser. No. 452,648, a ,May 3, 1965.his application Dec. 23, 1966, Ser.

604, 14 a 's tllaims. (Cl m-483) a 'ABSTRAQT OF THE DISCLGSURE In eachof the two disclosed embodiments of a thermally powered refrigerationsystem an ejector is so interrelated with an evaporation heatexchanger,.which receives a solutionof refrigerant ,andabsorbentmaterial from an absorber, that the ejector pumps refrigerantvapor from the evaporation-heat exchanger to a refrigerant condenser forcondensing, to thereby minimize the cost of the refrigerationsystemwhile still maintaining a high coefficient of performance for thesystem. The ejector in each embodiment also cooperates with associatedapparatus in the particular embodiment to effect-a precooling of therefrigerant before it enters a refrigerant evaporator for evaporation.,Several two.component refrigerants are disclosed which can. beeffectively used in each of the two embodiments to further improve theircoefficient of performance.

This application is a continuation-in-part application of United Statespatent application Ser. No. 452,648, filed by applicant on May 3, 1965,now Patent No. 3,298,- 196, and entitled Dynamic Pump Type RefrigerationSystem31 @This invention relates to refrigeration systems andrefrigerants used therewith, ,and more particularly to nonmechanicalthermally powered refrigeration systems employing ejectors andthosefluorocarbon refrigerants that will give nonmechanical thermally-poweredsystems a highly desirable coefficient of performance in addition to thequality of safety inherent in fluorocarbon vapors.

! In thedynamicpump type refrigeration system described in theabove-mentioned patent application both an ejector and a condenserassisted by absorption cooperate in athermally powered system to pumprefrigerant vapor of effectively a single component from an evaporatorto a condenser in such an arrangement that the ejector draws refrigerantvapor directly from the evaporator and discharges it ,into thecondenserassisted by absorption at a pressure less than that required forcondensation in a condenser unassisted by absorption. The condenseraided by ab sorption -reduces the back pressure on the ejector so theejector can pump more refrigerant vapor from the evaporator. The powervapor for the ejector is largely absorbent vapor. 1 V

, The refrigeration system shown and described in the present,application has incorporated therein some of the components of therefrigeration system shown in FIG. 1 of theaforementioned patentapplication Ser. No. 452,648; howeverin contrast thereto in the twoembodiments (FIG. I and "FIG. 4) "shownheriinfa pu'r'np means,specifically an ejector, and an absorber cooperateto pump refrigerantvaport'o a condenser in such manner that the absorber draws-vapordirectly from the evaporator, and the ejector cooperates byreceivingrefrigerant vapor supplied at a pressure above that withintheevaporator and delivers it directly to 'the condenser..-'The ejectorcooperates with the absorber through-:an-evaporation heat exchanger tohelp the absorber to pump more refrigerant vapor from the evaporatorwith much'less heat exchange and much less solution of refrigerant andabsorbent material circulating between the absorber aud the boilergenerator than would be necessary for operation of a normal typeabsorption type refrigeration system. The power vapor for the ejector inthe present application is mostly refrigerant vapor. In addition, thesystem is matched with special refrigerant combinations to take thefullest advantageof physical and thermodynamic properties with a twocomponent fluorocarbon refrigerant. Additional improvements are made byadding a refrigerant precooler and by so constructing the boilergenerator that it has an additional function.- f

In absorption type refrigeration systems it is necessary to repeatedlyor cyclically separate refrigerant from the absorbent material that hasabsorbed much refrigerant, hereafter referred to as rich solution, bymeans of a boiler. The absorbent material must have a relatively highboiling point to effect good separation of the refrigerant from theabsorbent material by distillation. At a given pressure the boilingpoint of a solution of refrigerant and absorbent material variesinversely with the molar proportion of refrigerant contained in theabsorbent material so that at the end of the distillation process in theboiler when the proportion of refrigerant dissolved in the absonbentmaterial is relatively small, hereafter referred to as weak solution,the boiling point of such weak solution may be very high. Although frompurely thermodynamic considerations a very high boiler temperature is anadvantage, in practice the very high boiler temperature inherent in asingle pressure prior-art type boiler will limit the net amount of heatreceived from the fuel source because of boiler heat radiation and otherlosses and will effect chemical decomposition of refrigerant andabsorbent material and corrosion of associated apparatus, and will alsoincrease the necessary area of heat transfer surfaces for the heatingand cooling of circulating solutions of refrigerant and absorbentmaterial with resulting increase in initial cost of the refrigerationsystem.

In refrigeration cycles the temperature of the refrigerant in thecondenser, which supplies refrigerant liquid to the evaporator, isgreater than the temperature of the refrigerant in the evaporator. Asrefrigerant liquid has a specific heat which is considerably higher thanthat of vaporized refrigerant leaving the evaporator, prior-art heatexchangers between incoming refrigerant liquid to the evaporator andoutgoing refrigerant vapor from the evaporator can only partiallyprevent incoming refrigerant liquid from carrying large quantities ofparasitic heat to the evaporator.

In any refrigeration cycle using a condenser and an evaporator, heat isabsorbed in the evaporator because of the heat of vaporization of therefrigerant. But as parasitic heat is carried back to the evaporator byvirtue of the specific heat of the liquid refrigerant, it is necessaryto use a refrigerant liquid that has a large-value heat of vaporizationas well as low specific heat. But a refrigerant must also have a lowboiling point, and the general rule with single component refrigerantsis that the boiling point increases in proportion with the molar heat ofvaporization. This rule is especially true with nonpolar fluorocarboncompounds, as illustrated by the graph of FIG. 2.

Ejectors as used in a refrigeration system have a tendency to decreaserapidly in fluid flow ratio between the secondary and the primary as theratio of discharge pressure to secondary or load intake pressureincreases toward a cut-off limit. It is also true that absorptionsystems, as well as ejector type systems, are very adversely affected bylarge pressure ratios between the condenser and the evaporator asdetermined by the temperature difference between the ambient temperatureof the absorber and the condenser, and the temperature of theevaporator; and this adverse effect may be severe in cases where theabsorber and condenser are cooled by ambient air. Refrigerants that havehigh molar heats of vaporization also tend to have larger ratios ofvapor pressure between two given temperatures. For example, between thetemperatures of F. and 115 F. the vapor pressure increases 3.47 fold ForCClF -CClF (R114) which has a molar heat of va- Jorization of 10,000B.t.u., while the vapor pressure in- :reases 3.88 fold for CCl F (R11)which has a molar heat )f vaporization of 10,760 B.t.u. Thus simpleabsorption systems or simple ejector systems with single componentluorocarbon working substances operate with limited co- :fficient ofperformance, and this limit is lower if there is a large temperaturedifference between the evaporator and the ambient temperature of theabsorber and the :ondenser.

Therefore an object of this invention is to provide a thermally poweredrefrigeration system in which a pump means, specifically an ejector,cooperates with an absorption system in such a way that the absorberreceives more refrigerant vapor from the evaporator, thus giving thesystem a high coefiicient of performance and low fuel cost.

Another object of this invention is to provide a thermally poweredrefrigeration system in which a pump means, specifically an ejector,cooperates in such a way with an absorber to reduce the required liquidheat exchange, and thus to reduce the cost of the overall system.

Another object of this invention is to provide a thermally poweredrefrigeration system that can use safe fiuorocarbons for working fluidsso it is safe to build the system as a packaged unit for insideinstallation. Another object of this invention is to provide in athermally powered refrigeration system means for reducing the quantityof liquid circulating to and from a high pressure boiler, to thus reducethe electric power cost for pumping such liquid.

Another object of this invention is to provide a thermally powered airconditioning system in which a pump means, specifically an ejector,cooperates with an absorber such that the absorber and condenser of thesystem can be cooled with ambient air.

Another object of this invention is to provide a thermally poweredrefrigeration system combining a pump means, specifically an ejector,with a two stage absorber so that the second stage of the absorber iscooled so that it absorbs more refrigerant vapor from the evaporator.

Another object of this invention is to provide a thermally poweredrefrigeration system in which a pump means, specifically an ejector,cooperates with the system in such a manner that refrigerant vapor iswithdrawn from the system at a pressure that is intermediate betweenthat of the condenser and the evaporator and is returned directly to thecondenser from the ejector, thus allowing the absorbent material in theabsorber to absorb more refrigerant vapor before the rich solution ispumped to the boiler.

Still another object of this invention is to combine in a thermallypowered refrigeration system a boiler generator means by which vaporrefrigerant is separated from the absorbent material at more than asingle pressure to thereby reduce the temperature of the final andweakest solution of refrigerant and absorbent material, to thus protectthe refrigerant and absorbent material from thermal decomposition.

Still another object of this invention is to combine a pump means,specifically an ejector, in an absorption system such that the ejectoruses vapor already generated by the boiler of the absorption system' toeffect a precooling of refrigerant liquid that is returning to theevaporator.

Still another object of this invention is to provide in a thermallypowered refrigeration system a relatively nontoxic and nonfiammablerefrigerant having two components of somewhat restricted solubility insuch a mixture that one component can be absorbed more readily than theother and so that the ratio of the condenser pressure to the evaporatorpressure for the mixture is less than the ratio of condenser pressure toevaporator pressure for one of the components taken at the correspondingcondenser and evaporator temperatures, to thereby increase thecoefiicient of performance of the refrigeration system.

Other objects of this invention will become apparent from the followingdescription when taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is a schematic diagram of one embodiment. of this invention inwhich an ejector is employed in a thermally, powered refrigerationsystem to. lower. the temperature of an evaporation heat-exchanger toincrease refrigerant vapor absorption within the system;

FIG. 2 is a straight'line graph showing that for nonpolar fluorocarbonrefrigerants the heats of vaporization for the various examples are inlinear relation to" the respective boiling points, but that the polarfluorocarbon refrigerants have abnormally large 'heats' of vaporizationcorresponding to given boiling points;

FIG. 3 are graphs showing'the vapor pressures of mixtures of CHCl F(R21) and CClgF (R11) refrigerants in varying molar proportions at 45 F.and F.

FIG. 4 is a schematic diagram of another embodiment of this invention inwhich an ejector is employed in a thermally powered refrigeration systemto cause reevaporation of refrigerant in the system and the return ofthe resulting refrigerant vapor directly to the condenser forcondensing.

Referring to FIG. 1 there is shown a thermally powered refrigerationsystem 10 illustrating one embodiment of this invention. Therefrigeration system 10 will operate with a single componentrefrigerant, but it-will operate better with a two component refrigerantsuch as CHClgF (R21) and CCl F (R11). Operation will first be explainedwith a single component refrigerant, and later with a two componentrefrigerant so as to set forth further teachings of this invention.

A boiler 12 is heated from a heat source, not shown, and generatesrefrigerant vapor under relatively high pressure to power an ejector 13and to separate refrigerant from absorbent liquid material. An analyzer16, which is closely associated with and is part of the boiler 12,functions to further separate refrigerant vapor from absorbent vapor bycondensing out absorbent vapor. The analyzer 16 contains a boiler inlettube 14 and a boiler outlet tube 18 spiralled very close to one anotherin heat transfer relationship, with the outlet tube 18 extending pastthe inlet tube 14 to near the bottom of the boiler 12.

The ejector 13 comprises power inlet means 20, refrigerant inlet means22 and discharge means 24 and preferably is of the centrifugal typedisclosed in US. Patent No. 3,215,088 or in FIG. 2 of US. Patent No.3,298,196. The power inlet means 20, of the ejector 13, is operativelyassociated with the boiler 12 for receiving refrigerant vapor therefrom.On the other hand, the refrigerant inlet means 22 of the ejector 13 isoperatively associated with an evaporation heat exchanger 26 for drawingrefrigerant vapor therefrom. The discharge means 24, of the ejector 13,is operatively associated with a condenser 28 to discharge refrigerantvapor into the condenser 28 for condensing. In other words, the ejector13 functions as a vapor pump to pump secondary refrigerant vapor fromthe evaporation heat exchanger 26 and deliver the vapor to be condensedat a higher pressure to the condenser 28. The high pressure power vaporfor the ejector 13 comes from' the boiler 12 through a power vaporsupply con-' duit 30. V

The term flow ratio as usedherein with reference to the ejector 13refers to the ratio ofmoles of secondary re-. frigerant vapor pumped inthrough a conduit 32to the number of moles of primary power vaporsupplied through the conduit 30. The effectiveness of the ejector 13 isgenerally proportional to its flow ratio. The flow ratio ofrthe ejector13 can be improved by having a small ratio ofdischarge pressure at thecondenser 28 to the pressure of the secondary refrigerant vapor withinthe conduit32, and also by having the primary power vapor within thec0n'- duit 30 delivered at higher pressure, and further-by having theprimary power vapor within the conduit 30 of higher 5 molecular weightthan that of the secondary vapor within the conduit 32. i

The condenser 28 is of the conventional finned type and is cooled byambient air. A lower portion 34 of the condenser 28 functions toaccumulate condensed and liquifi'ed refrigerant. In order to regulatethe flow of liquid refrigerant ffom the condenser 28 to the evaporationheat exchanger 26 through a conduit 36, a flow regulator 38 is provided;The flow regulator 38 prevents refrigerant vapor from flowing from thecondenser 28 and through the conduit 36.

An absorber 40 has two main parts, a high temperature section 42 and anambient temperature section 44 with radiation fins 46 for dissipatingheat at ambient temperature, and houses a preheat exchanger 48 which isshown as a tube that is formed into a helical coil and through which arich solution of absorbent material and dissolved refrigerant flows soas to be preheated on its way back to the boiler .12. A conduit 50 isinter-connected between the outlet tube 1 8, of the boiler 12, and thetop of the high temperature section 42, of the absorber 40, fordelivering a weak solution of refrigerant and absorbent material to theabsorber 40. A distributor 52 is disposed within the absorber 40 so thatsuch weak solution entering from the conduit 50 is restricted in flowand spreads out over the surface of the coiled preheat exchanger 48 inabsorbing contact with refrigerant vapor received from a finnedevaporator 54 which provides a cooling effect to the space to be cooledor refrigerated. The refrigerant vapor from the evaporator 54 enters thehigh temperature section 42, of the absorber 40, at evaporator pressureby means of a conduit 56 and heats the preheat exchanger 48 and the richsolution therein with which it is in thermal contact, as refrigerantvapor is absorbed within the high temperature section 42 and liberatesits heat of vaporization. As the liquid absorbent material within thehigh temperature section 42 becomes laden with refrigerant, theresulting rich solution drops into the ambient temperature section 44,of the adsorber 40, where more refrigerant vapor can be absorbed at thelower ambient temperature.

The evaporation heat exchanger 26 includes an outer compartment 62 whichis insulated from ambient heat, and an inner compartment 64 whichfunctions as an evaporator. The evaporation heat exchanger 26 isoperatively associated with the absorber 40 and with the condenser'28 sothat a solution of refrigerant and absorbent material passes from theabsorber 40 into the outer compartment 62, of the evaporation heatexchanger 26, and so that condensed refrigerant passes from thecondenser 28 into the inner compartment 64 of the evaporation heatexchanger 26. The evaporation heat exchanger 26 is also operativelyassociated with the evaporator 54 so that a portion. of the refrigerantevaporated within the evaporator 54 passes into the outer compartment 62of the evaporation heat exchanger 26 and is absorbed by the cooledabsorbent material within the outer compartment 62. In particular, theremaining refrigerant vapor in the ambient temperature section 44, ofthe absorber 40, which has been received from the evaporator 54 and hasnot been absorbed in the absorber 40, passes from the ambienttemperature section 44, of the absorber 40, through a connecting conduit58 to the evaporation heat exchanger 26. Absorbent liquid material andits dissolved refrigerant drains to the outer compartment 62, of theevaporation heat exchanger 26, by a conduit 60 and is disposed in heattransfer relationship with theinner compartment 64. Liquid refrigerantenters the inner compartment 64, which is at a pressure above thepressure within the evaporator 54, by means of the conduit 36.Refrigerant vapor is pumped out of the inner compartment 64 by theejector 13 and cooling results from evaporation of a portion of theliquid refrigerant disposed within the inner compartment 64. Theremaining portion of the liquid refrigerant disposed within the innercompartment 64 is cooled;

and absorbent material with dissolved refrigerant dis posed within theouter compartment 62 is llkCWlSl cooled several degrees below ambienttemperature as i flows from the conduit-60 and trickles down over throuter surface-of the cool inner compartment 64, ofth evaporation heatexchanger 26,. in absorbingcontact witl refrigerant vapor received fromthe conduit 58. The ab sorbent material thus cooled acquires thecapacity to ab sorb considerably more refrigerant vapor, therefore morerefrigerant vapor is absorbed by the absorbent material tc thus becomea. rich solution of refrigerant and absorbent material, and heat thusliberated is removed by evaporation of refrigerant liquid within theinner compartment 64.

In order to pump the rich solution of refrigerant and absorbent materialfrom the outer compartment 62 of the evaporation heat exchanger 26through the preheat exchanger 48 of the absorber 40 and into the inlettube 14, of the analyzer 16, a pump 66 and conduit means 68 is provided.

The remaining cooled liquid refrigerant disposed within the innercompartment 64, of the evaporation heat exchanger 26, is conveyed to theevaporator 54 by means of a syphon tube 70 which has a flow restriction72 for reg- ,ulatin'g the flow of liquid refrigerant to the evaporator54. The inner compartment '64, of the evaporation heat exchanger 26,thus also functions as a refrigerant precooler for the refrigerantliquid conveyed to the evaporator 54.

The evaporator 54 as illustrated is of the conventional finned type'which evaporates, at reduced pressure, refrigerant liquid which isreceived through the siphon tube 70, and thereby cools and refrigeratesthe surrounding space. Resulting cool refrigerant vapor leaves theevaporator 54 through the conduit 56 in heat transfer relationship withthe syphon tube 70 and the refrigerant liquid therein in order tofurther cool the refrigerant liquid flowing to the evaporator 54 throughthe syphon tube 70.

In order to prevent any nonevaporated liquid refrigerant fromoverflowing from the evaporator 54 and into the absorber 40, whichaction would dilute and weaken the absorbent material in the absorber40, a sump 74 is provided to collect such overflow of liquidrefrigerant. A conduit 76 is interconnected between the sump 74 and thepump 66 so as to return such collected overflow re frigerant to theboiler 12.

The operation of the refrigeration system 10 as shown in FIG. 1 will nowbe described in its simplest operation with a refrigerant of onevolatile component and an absorbent material that is much less volatile.Liquid absorbent material containing a relatively high concentration ofdissolved refrigerant, in other words rich solution, is pumped into theheated boiler .12 by way of the inlet tube 14, of the analyzer 1'6, andonto the surface of the outlet tube .18 so as to vaporize a portion ofthe refrigerant dissolved in the incoming rich solution, whichrefrigerant vapor flows or passes into the power inlet means 20 of theejector 13. The remaining refrigerant and the absorbent in which it isdissolved settles downward in the boiler 12 at a higher temperature as aless rich solution. As more refrigerant is boiled off the solutionbecomes weakest at the bottom of the boiler 12 where the temperature isthe highest. Some absorbent is boiled off with the refrigerant from theweak solution in the boiler 12, but most of the vaporized absorbentcondenses on the outer surface of the inlet tube 14 and gives up heat topreheat the rich solution of refrigerant and absorbent material enteringthe boiler 12 and to vaporize a portion of the dissolved refrigerant toadd to that vapor passing through the conduit 30 to the power inletmeans 20 of the ejector 13.

The boiler 12 must -be heated to a sufiiciently high temperature toproduce vapor at a pressure sufficiently high to power the ejector 13. Arelatively hot weak solution of refrigerant and absorbent materialleaves the bottom of the boiler 12 by means of the outlet tube 18 andgives up much of its heat to further heat the rich soution ofrefrigerant and absorbent material flowing downvard in the inlet tube 14and over the surface of the outet tube 18. Such weak solution then flowsby way of the :onduit 50 to the absorber 40. The weak solution which snow .partly cooled enters the absorber 40 at the top of ts hightemperature section 42 and is distributed by the listributer 52overthe-surface of and in thermal contact with the preheat exchanger 48where such weak solution s in absorbing contact with refrigerant vaporcoming fromthe evaporator 54 by way of the conduit 56 at evaporatorpressure. As refrigerant vapor is absorbed by :heweak solution, theresulting heat of vaporization givan up by the absorbed refrigerantvapor is transferred to the rich solution that is disposed within thepassage'of the preheat exchanger 48 and that is on its way back to theboiler 12. As a solution of refrigerant in absorbent will take on morerefrigerant vapor as the solution drops in temperature, furtherabsorption of refrigerant vapor takes place as the solution runs downinto the cooler ambient temperature section 44 of the absorber 40. Therefrigerant vapor-laden liquid absorbent material then flows through theconduit 60 into the outer compartment 62, of the evaporation heatexchanger 26, over the outer surface 80 of the inner compartment 64where it is further cooled to below ambient temperature in contact withrefrigerant vapor which flows from the absorber 40 and through theconduit 58 to the outer compartment 62 where the pressure is still thesame as within the evaporator 54. Here the absorbent solution reachesits greatest degree of saturation with refrigerant vapor. This richsolution is then pumped out of the outer compartment 62, of theevaporation heat exchanger 26, through the conduit means 68 and thepreheat exchanger 48, of the absorber 40, back to the inlet tube 14 ofthe analyzer 16. This rich solution is preheated while passing throughthe preheat exchanger 48.

The vapor produced in the boiler 12 is directed through the conduit andinto the power inlet means 20 of the ejector 13 which, by action of theejector 13, effects a reductionlof pressure at the refrigerant inletmeans 22, of the ejector 13, so that refrigerant vapor is pumped fromthe inner compartment 64 of the evaporation heat exchanger 26. Thecombined power vapor and the pumped secondary vapor, substantially allof which is refrigerant, is compressed and discharged into the condenser28 through the discharge means 24 of the ejector 13. The dischargepressure of the refrigerant vapor discharged into the condenser 28 issufficient that the refrigerant condenses to a liquid near ambienttemperature in the condenser 28, and the heat of condensation that isliberated is dissipated to the ambient air by means of the radiationfins 82.

The refrigerant that condenses in the condenser 28 flows through theflow regulator 38, such as a float valve, and through the conduit 36into the inner compartment 64, of the evaporation heat exchanger 26,where the pressure is less than that in the condenser 28 but is greaterthan that in the evaporator 54. Here in the inner compartment 64 aportion of the condensed refrigerant evaporates and passes to therefrigerant inlet means 22 of the ejector 13, but the remaining portionof the condensed refrigerant disposed within the inner compartment 64that is cooled leaves by way of the restriction 72 through the syphontube 70 and into the evaporator 54. Here in the evaporator 54 therefrigerant evaporates thus providing a cooling effect, and therefrigerant vapor thus produced is conducted to the absorber 40 by wayof the conduit 56.

The absorbent material suitable for use in an absorption refrigerationsystem must have a high boiling point, must be chemically stable, shouldhave low molecular specific heat, must be reasonably inexpensive, mustbe noncorrosive, and must be compatible with the refrigerants chosen.Water has a reasonably high boiling point and might appear to beexcellent because it is a good solvent and appears to satisfy most ofthe other conditions. But water is a very highly polar liquid, thereforerefrigerants of sufficiently low boiling point must also be highly polarto be sufliciently soluble. Such water soluble refrigerants as ammoniaand sulfur dioxide are toxic, flammable, or corrosive. 0n the otherhand, fluorocarbons are usually stable, nontoxic and nonflammable,butare uncompatible with water. Therefore, it is desirable that both theabsorbent material and the refrigerant be fluorocarbons. The fewinexpensive. fluorocarbon compounds having high boiling points and highcritical temperatures seem to be nonpolar. A satisfactory example of afluorocarbon absorbent is difluorotetrachloroethane CCI F CCI F (R112)that has the following physical properties: Boiling point'199 F., molarspecific heat 42 B.t.u., molecular weight 203.9.Trifluorotrichloroethane CC1 F-CClF (R113) may also be used as anabsorbent material for lower boiling point refrigerants. It has thefollowing physical properties: Molecular weight 187, boiling point 118F., molar specific heat 40.8 B.t.u.

Fluorocarbon refrigerants for air conditioning should have boilingpoints in the temperature range under 50 F., should be relativelyinexpensive, should have low molecular weight and specific heat, andshould have high heats of vaporization. Also they must be nearlyperfectly soluble in the absorbent as shown by a nearly straight linerelationship between their total vapor pressure and the molar proportionof refrigerant in absorbent material. Furthermore, the ratio of thevapor pressure of the refrigerant at condensing temperature to the vaporpressure at evaporating temperature should be as small as possible inorder that the absorbent liquid material 'at saturation can have thegreatest molar proportion of dissolved refrigerant.

Two physical properties, boiling point and heat of vaporization, ofseveral available and for the most part relatively inexpensivefluorocarbons are compared by a line graph in FIG. 2. The fluorocarbonsCClF -CF (R), CCI F (R12), CBrClF (R12B1),

(R114), CCl F (R11), Ccl F-CClF (R113) and CBrF -CBrF (R114B2) along thestraight line of FIG. 2 are nonpolar while the three fiuorocarbons,CHCIF (R22), CHF -CClF (R124a) and CHCI F (R21), have abnormally highheats of vaporization and are polar. These three polar fluorocarbons aresufficiently different from the other nonpolar fluorocarbons includingR112 as to restrict the solubility of the polar fluorocarbon in anonpolar fluorocarbon liquid, which restriction makes the vapor pressureof such a solution to deviate above the straight line molar proportionversus pressure representing Raoults law. A similar deviation is shownin FIG. 3 for the polar and nonpolar compounds of R21 and R11,respectively, A similar difference affecting mutual solubility existsbetween R22 and R12 to cause a similar deviation from Raoults law.However this deviation above the line will be shown to be an advantagein the case of two refrigerant components one of which is polar and theother nonpolar.

Vapor pressures increase rapidly with temperature for the separatefluorocarbon liquids with large values of heat of vaporization, as isillustrated by approximate val ues in the folowing table: i

But as taken from FIG. 3 and shown in the last row of the above table, aliquid mixture of a polar fluorocarbon refrigerant and a nonpolarfluorocarbon refrigerant can have a smaller ratio of vapor pressure at115 F. to vapor pressure at 45 F. than is the case of a single liquidcompound component, without sacrificing either the vapor pressure or theheat of vaporization of the individual components. In addition, therefrigerant mixture can be chosen so that selective absorption in favorof the nonpolar component of the refrigerant mixture can take place inthe absorbent material, thus causing the total vapor pressure of theresulting solution of refrigerant and absorbent material to rise lessthan would be the case with the same number of moles of the polarcomponent such as R21 being absorbed alone. Also some separation onevaporation of a two component refrigerant can take place so that thelighter polar component will dominate in producing a vapor of lowermolecular weight. This resulting lower molecular weight is an advantagewhen the vapor serves as secondary vapor pumped by an ejector.

The effect of a two component refrigerant in the absorber 40 and in theouter compartment 62, of the evaporation heat exchanger 26, will now bedescribed. As hereinbefore mentioned, R21 is polar and R11 is nonpolarthus restricting the mutual solubility of the two components so that thetotal vapor pressure of the refrigerant liquid mixture of R21 and R11 inthe evaporator 54 is greater than the vapor pressure obtained by astraight line molar interpolation based on the vapor pressures of pureR11 and of pure R21 taken separately, as shown by the curves of FIG. 3.In other words the two liquid refrigerant mixture of R21 and R11 has avapor pressure that is greater than would be given by Raoults law.Furthermore, test results associated with the curves of FIG. 3 and otherrefrigerant mixtures such as R21 and R114 have shown that for mixedliquid compositions in a region to the left of the peak of the vaporpressure curve when such a peak occurs, that is to say in a region ofcomposition in which there is a greater proportion of nonpolarrefrigerant than at the peak of the curve, the vapor phase ofrefrigerant mixture has a greater molar proportion of polar componentthan the proportion of polar component in the liquid phase from whichthe vapor originated. Tests have also shown that the reverse is true tothe right of the peak of the curve, while at the peak of the curve thecomposition of the vapor is more nearly like that of the liquid phasewith which it is in equilibrium. But in the vapor phase the partialvapor pressure of each refrigerant component is proportional to itsmolar fraction of the total vapor, independent of polarity and otherphysical properties. Therefore a composition range of R21 and R11 existsin which the partial vapor pressure of nonpolar component is at least asgreat a proportion of the total vapor pressure as the proportion ofnonpolar component in the liquid refrigerant mixture from which itevaporated. Also the molar amount of a given vapor component that anonpolar absorbent material will absorb from a limitless supply ofrefrigerant vapor mixture is inversely proportional to the volatility ofthe given component, is less if the component is polar rather thannonpolar, and is proportional to the partial vapor pressure of the givencomponent. Thus from a limitless supply of a refrigerant vapor mixtureof equal molar parts of R21 and of R11 a liquid absorbent material suchas R112 will absorb more of the nonpolar R11 than of the polar R21.

In operation therefore proportionally more moles of the nonpolarfluorocarbon R11 than R21 is absorbed within the absorber 40 at thebeginning in the high temperature section 42. of the absorber 40, wherethere is effectively a limitless supply of mixed refrigerant vaporentering, thus reducing the amount of R11 in the refrigerant vapormixture that passes on to the cooler ambient temperature section 44 ortothe still cooler outer compartment 62, of the evaporation heatexchanger 26, where absorption of the remaining refrigerant vapor takesplace. As it takes'more moles of the less volatile and nonpolar R11 toraise the vapor pressure of a solution of a refrigerant and a nonpolarabsorbent to a given equilibrium pressure level than it would take of apolar and more volatile refrigerant component like R21, selectiveabsorption of R11 in the high temperature section 42, of the absorber40, in contact with an effectively limitless stream of mixed refrigerantvapor brings about absorption of a greater total number of moles ofrefrigerant vapor in the high temperature section 42 and a correspondingdecrease in the total remaining moles of refrigerant vapor absorbedwithin the outer compartment 62 of the evaporation heat exchanger 26.Thus proportionally more heat is liberated at the higher temperaturelevel within the absorber 40 than would be liberated if only one ofeither R11 or R21 were being absorbed in the absorber 40 as a singlecomponent refrigerant, and similarly proportionally less heat isliberated in the outer compartment 62 of the evaporation heat exchanger26. Of course a two component refrigerant of polar R22 and nonpolar R12could be used to produce the aforementioned deviation from Raoults lawand also effect the aforementioned selective absorption so that more R12would be absorbed in the high temperature section 42 and less on theouter compartment 62, of the evaporation heat exchanger 26, so that moreheat would be liberated in the high temperature section 42 and so lessheat would be liberated in the outer compartment 62 of the evaporationheat exchanger 26.

The overall operation of the refrigeration system 10 shown in FIG. 1will now be described with a two component refrigerant of R21 and R11chosen as an example and with R112 as an example of absorbent material.However it is to be understood that for instance, a two componentrefrigerant such as R22 and R12 could also be used in the refrigerationsystem 10 with R112 or R113 as the absorbent material. Varying operatingconditions and engineering details make the molar proportions of thethree liquids of the system vary at any point in the system, so examplesof molar proportions at various points of the system can only be givenin relative trends that help to clarify features of the invention. Allpercent proportions of fluorocarbon compounds illustrated hereafter willbe in molar percent proportions.

The densities at 77 F. of the example two refrigerant components R21 andR11 and liquid absorbent material R112 are as follows: density of R21,85.28 pounds per cubic 'foot, density of R11, 92.1 pounds per cubicfoot, and density of R112, 102 pounds per cubic foot.

The weak solution of R11, R21 and R112 in the bottom of the boiler 12has settled there because it has become nearly depleted of R21 and R11,having the assumed proportions of 92% R112, 6% R11 and 2% R21, and hashigher density than a rich solution of R11 and R21 in R112 as can bedetermined by the above relative densities. For example, boilingmay'take place in the boiler 12 near 300 F. at a boiler pressuresufficient to operate the ejector 13. This hot weak solution in theboiler 12 is partially cooled as it leaves the outlet tube 18, of theanalyzer 16, and before it is sprayed over the preheat exchanger 48, ofthe absorber 40, in absorbing contact with refrigerant vapor of assumedcomposition 50% R21 and 50% R11. In the high temperature section 42, ofthe absorber 40, proportionally more R11 than R21 is absorbed becauseofthe higher boiling point and lower volatility of R11, and theliberated heat of vaporization raises the temperature of such weaksolution as well as the preheat exchanger 48 with which such weaksolution is in contact to approach an equilibrium value between ambienttemperature and the temperature of the boiler 12. The equilibriumtemperature is that temperature at which the total vapor pressure ofsuch weak solution equals the vapor pressure within the evaporator 54containing 50% R21 and 50% R11. As more R11 and R21 is absorbed by thissolution moving downward within the high temperature section 42, thisequilibrium temperature drops to near ambient temperature.

At this equilibrium temperature it is probable that the richer solutionhas come to the proportions 72%-R112, R11 and 8% R21 by the time itflows downward into the cooler outer compartment 62, of the evaporationheatexchanger 26, having absorbed an additional twenty percent (20%)refrigerant mixture. If the entering weak solution had simply absorbedequal amounts ofRll and R21 fromthe 50% R21 and 50% R11 refrigerantvapor the total equilibrium vapor pressure would-have been reached whenthe absorbent solution came to the, pro.- portions of 76% R112, 14% R11and 10% R21, then having'absorbed but 16% additional refrigerantmixture. Thus, there has actually, been something like one quarter morerefrigerant vapor absorbed in the absorber 40. The remaining refrigerantvapor containing a greater proportion of R21 than R11 passes from theabsorber 40 on into the outer compartment 62, of the evaporation heatexchanger 26, so that the final rich solution disposed in the bottom ofthe outer compartment 62 reaches the proportions 60% R112, 22% R11 and18% R21 by the time the last remnant of refrigerant vapor is dissolved.As the composition of the final rich solution of refrigerant andabsorbent material is effectively determined only by the temperaturewithin the inner compartment 62, of the evaporation heat exchanger 26,and the vapor pressure of the original 50% R21 and 50% R11 refrigerantexisting in the evaporator 54, any additional refrigerant vapor absorbedin the absorber 40 reduces the proportion of refrigerant vapor absorbedin the inner compartment 62 of the evaporation heat exchanger 26 andthus reduces the proportion of heat of vaporization that must beabsorbed by the action of the evaporation heat exchanger 26. Thispermits the ejector 13 to further reduce the pressure of the refrigerantvapor within the inner compartment 64, of the evaporation heat exchanger26, which in turn reduces the temperature therein to thus permit thefinal rich solution of refrigerant and absorbent material within theouter compartment 62 to require a greater concentration of refrigerantin absorbent material.

The composition of power vapor delivered to the ejector 13 is the same50% R21 and 50% R11 as in the evaporator 54, and-has a molecular weightof 119.9. Also the composition of the vapor evaporated from the 50% R21and 50% R11 refrigerant liquid within the inner compartment 64 of theevaporation heat exchanger 26 is more nearly 65% R21 and R11, withcorresponding molecular weight of 111.8. Thus the molecular weight ofthe secondary vapor supplied to the ejector 13 is less than themolecular weight of the power vapor coming from the boiler 12. Thisdifference in molecular weight between power vapor and secondary vaporincreases the efiiciency of the ejector 13 as a pump.

Referring to FIG. 4 there is illustrated another embodiment of theteachings of this invention in which like components of FIGS. 1 and 4have been given the same reference characters.

A heated boiler 112, heat source not shown, functions to separaterefrigerant vapor from a rich solution of refrigerant and absorbentmaterial and to direct refrigerant vapor under pressure to a conduit 114through which the refrigerant vapor flows to the power inlet means 20 ofthe ejector 13. An analyzer 116 operates at the same pressure as in thecorresponding analyzer 16 of FIG. 1 and an inlet tube 118 and an outlettube 120 function in a similar manner as the corresponding tubes 14 and18 in FIG. 1 to separate refrigerant vapor from absorbent material. Buta pressure and flow control means 122 permits the outer compartment 124,of the boiler 112, to operate at a lower pressure than the innercompartment 126 of the boiler 112 so that additional refrigerant vaporcan be separated from the absorbent material and so that the weaksolution of refrigerant and absorbent material leaving the boiler 112 ismore nearly completely separated absorbent. To do the same degree ofseparating at the higher pressure withinthe inner compartment 126, ofthe boiler 112, would .require a considerably higher boiling temperatureand this higher boilingtem perature would effect a greaterdegreeofdecomposition of the refrigerant and absorbent material.-The pressureandrfiow control means 122 is apressure compensated float valve, howeverother equivalent control mechanisms can be used. I t

The secondary refrigerant inlet means 22 of the ejector13 is operativelyassociated with an evaporation heat exchanger 128 for pumpingrefrigerant vapor from the evaporation heat exchanger 128 into therefrigerant inlet means 22, andthe discharge means 24, of the ejector13, is operatively associated with a conventional con? denser 130 todischarge refrigerant vapor into the condenser 130 for condensing. Also.the power inlet means 20, of the ejector 13, is operatively associatedwith the boiler 112 for receiving refrigerant vapor from the boiler 112.

A conduit 132 is interconnected between the outer compartment 124, ofthe boiler 112, and the condenser 130 so that refrigerant vapor passesfrom the outer com-v partment 124 to the condenser 130 for condensing. Afractionating section 134, of the conduit 132, is in thermal contactwith a solution of refrigerant and absorbent material which is disposedwithin the evaporation heat exchanger 128 and which is somewhat coolerthan the refrigerant vapor and any entrained absorbent vapor flowing inthe conduit 132 so that the less volatile absorbent vapor that isentrained with refrigerant vapor flowing in the conduit 132 is condensedout as liquid and returns to the outer compartment 124 of the boiler112.

The condenser 130 is cooled to near ambient temperature by ambient aircirculating over radiation fins 136. A precooler 138 is interconnectedbetween the condenser 130 and an evaporator 140 and with the refrigerantinlet means 22, of the ejector 13, so that condensed refrigerant flowsfrom the condenser 130 through a conduit 142 and a flow regulator 144into the precooler 138. The flow regulator 144 may be a conventionalfloat valve for regulating the flow of the liquid refrigerant from thecondenser 130 to the precooler 138.

In operation the ejector 13 reduces the pressure within the precooler138 so that a portion of the condensed refrigerant within the precooler138 evaporates, vthus cooling the remaining portion of the condensedrefrigerant within the precooler 138 before such.cooled remainingportion of refrigerant passes to theevaporator 140 through a fiowregulator 146 and a conduit 148. The fiow regulator 146 regulates theflow of cooled liquid refrigerant to the evaporator 140 and may be acon,- ventional float valve.

In order to pump and remove from the evaporator 140 refrigerant vaporthat evaporates within the evaporator 140 and absorb such refrigerantvapor, an absorber 150 is operatively connected to the evaporator 140 bymeans of a conduit 152. The absorber 150 includes a high temperaturesection 154, an ambient temperature section 156, having radiation fins158, a preheat exchange and a distributer 162.

The evaporation heat exchanger 128 includes a housing 164 for receivinga rich solution of, refrigerantand absorbent material from the absorber150. In particular, a rich solution of refrigerant and absorbentmaterial is pumped by means of a pump 166 from the ambient temperaturesection 156 and through a conduit means 168, through the preheatexchanger 160, through a conduit 170 and into the housing 164 of theevaporation heat exchanger 128. The evaporation heat exchanger 128, alsoincludes a helical shaped heat exchange tube 172 which is disposed inheat exchange relationship with the rich solution of refrigerant andabsorbent material ,disposed within the housing 164. In order to pass arelatively hot weak solution of.refrigerant and absorbent materialthrough the heat exchange tube 172Hofthe evaporation heat exchanger 1 28and into the high tern;

13 peratu're section 154, of the absorber 150, conduit means 174interconnects the heat exchange tube 172 with the outlet tube 120, ofthe boiler 112, and with the high temperature section 154 of theabsorber 150.

In order to'increase the absorbing capacity of the absorber 150, anopening 176 is provided in the conduit means 174 so that the weaksolution of refrigerant and absorbent material disposed'in the bottom ofthe housing 164, of the evaporation heat exchanger 128, flows into theopening 176 and returns to the high temperature section 154 of theabsorber 150. A restriction 178 is provided in the conduit means 174 soas to regulate the flow of hot weak solution of refrigerant andabsorbent material from the boiler 112 to the high temperature section154 of the absorber 150;

A boiler pump 180 is interconnected between the inlet tube 118, of theboiler 112, and the housing 164, of the evaporation heat exchanger 128,by conduit means 182 in order to pump the rich solution of refrigerantand absorbent material from the upper part of the housing 164 into theboiler 112.

The operation of the refrigeration system illustrated in FIG. 4 will nowbe described in a simple mode with a refrigerant of one volatilecomponent and a liquid absorbent material that is very much lessvolatile. However a two component refrigerant such as described withreference to the embodiment of FIG. 1 can be used in this system withsimilar advantages to those shown for the refrigeration system ofFIG. 1. Rich solution of refrigerant and absorbent material is pumpedinto the heated boiler 112 by way of the inlet tube 118 of the analyzer116. Refrigerant vapor is separated from this rich solution in theanalyzer 116 at high pressure and is conducted out through the conduit114 to the power inlet means to power the ejector 13; the separation ofthe refrigerant vapor being similar to that described with reference tothe refrigeration system 10 of FIG. 1. As the solution of refrigerantand absorbent material loses refrigerant by evaporation it becomes moredense than the aforementioned rich solution and settles to the bottom ofthe inner compartment 126 from where it is forced out through thepressure and flow control means 122 into the outer compartment 124, ofthe boiler 112, where the pressure is lower and is near that pressurewithin the condenser 130.

In the outer compartment 124, of the boiler 112, additional refrigerantvapor with some entrained absorbent vapor is boiled off at a pressurenear the pressure within the condenser 130, and this vapor leaves theouter compartment 124 by the conduit 132 and the fractionating section134 where absorbent is condensed to a liquid to be returned to theboiler 112 through the conduit 132 so that separated refrigerant vaporis delivered to be condensed to a liquid in the condenser 130. The hotweak solution of refrigerant and absorbent material left in the outercompartment 124 of the boiler 112 leaves through the outlet tube 120 andflows through the conduit means 174, the restriction 178, and the heatexchanger tube 172, of the evaporation heat exchanger 128, to the hightemperature section 154 of the absorber 150.

The weak solution of refrigerant and absorbent material from the boiler112 enters the top of the high temperature section 154, of the absorber150, and flows over the distributer 162 so the weak solution becomesdistributed over the surface and in thermal contact with the preheatexchanger 160 and is disposed in absorbing contact with refrigerantvapor coming from the evaporator 140 and at the same low pressure aswithin the evaporator 140. As refrigerant vapor is absorbed by such weaksolution entering from the boiler 112, resulting heat of vaporation thatis liberated is transferred to the rich solution of refrigerant andabsorbent material that is flowing within the preheat exchanger 160.This solution of refrigerant and absorber material becomes cooler andcontinues to absorb more refrigerant vapor as it 14 moves downward alongthe preheat exchanger 160.until it drops into the ambient temperaturesection 156, of the absorber 150, where further refrigerant vapor isabsorbed with liberation of heat of vaporation and the solution finallybecomes a rich solution of refrigerant and absorbent material.

The rich solution of refrigerant and absorbent material is pumped fromthe absorber by the pump 166'and through the preheat exchanger andthe'conduit 170 into the housing 164 of the evaporation heat excanger128. Such rich solution is preheated as it passes through the preheatexchanger 160 to aid in forming refrigerant vapor to be compressed bythe ejector, and a portion-of the absorbed refrigerant may be convertedto vapor under reduced pressure caused by pumping action of the ejector13 even before the preheated solution reaches the housing 164 of theevaporation heat exchanger 160. As the preheated rich solution reachesthe top portion of the evaporation heat exchanger 128 a portion of suchsolution enters the conduit means 182 to be pumped back to the boiler112 by the boiler pump 180, while the remaining portion of such richsolution receives additional heat from the hot weak solution ofrefrigerant and absorbent material flowing through the heat exchangetube 172, of the evaporation heat exchanger 128, and from heat ofcondensation due to hot absorbent vapor condensing within thefractionating section 134 so that a portion of dissolved refrigerant isevaporated from this remaining portion of rich solution within thehousing 164 at the reduced pressure caused by the pumping action of theejector 13. The resulting refrigerant vapor within the evaporation heatexchanger 128 is pumped back through a conduit 184 and the ejector 13 tobe condensed to a liquid in the condenser 130. The portion of solutionof refrigerant and absorbent material remaining within the housing 164of the evaporation heat exchanger 128 settles lower in the evaporationheat exchanger 128 as it becomes more dense on losing refrigerant ofless density by evaporation, and enters the opening 176 to combine withthe hot weak solution of refrigerant and absorbent material that isreturning to the high temperature section 154, of the absorber 150, fromthe boiler 112. In operation the pressure within the housing 164 isgreater than the pressure within the evaporator 140.

A portion of the liquid condensed refrigerant disposed Within theprecooler 138 is evaporated and the resulting refrigerant vapor ispumped from the precooler 138 by action of the ejector 13 through aconduit 186 and the conduit 184 so that the remaining portion of thecondensed refrigerant disposed within the precooler 138 is precooledbefore such cooled condensed refrigerant portion flows into theevaporator 140, thus allowing the space that surrounds the evaporator140 to be cooled Without carrying such a large amount of heat ofvaporization of the refrigerant to the absorber 150usince a portion ofthe heat of vaporization of the refrigerant is pumped from the precooler138 to the condenser 130 and the remaining cooled liquid refrigerantflowing into the evaporator 140 can still do as much cooling of thespace to be cooled as a larger amounts of non precooled refrigerant can.

It is to be understood that the boiler 12 of FIG. 1 can be connected inthe refrigeration system of FIG. 4- in place of the boiler 112. Ofcourse the conduit 132 and the fractionating section 134 would beremoved if such a substitution were made.

The apparatus embodying the teachings of this invention has severaladvantages. For instance, a refrigeration system constructed inaccordance with the teachings of this invention can operate efficientlywith safe fluorocarbon working mediums. In addition, a refrigerationsystem constructed in accordance with the teachings of this inventioncan operate efllciently with ambient air cooling of the absorber and thecondenser. Further, the cost of such refrigeration systems in minimized.Also, the efficiency of such refrigeration systems constructed inaccordance with the teachings of this invention can be further increasedby utilizing selected pairs of fluorocarbonrefrigerants as hereinbeforedescribed. Since certain changes may be made in the above describedapparatus and different embodiments of the invention may be made withoutdeparting from the spirit andthe scope thereof, it is intended that allmatter containedin-theabove description or shown in the accompanyingdrawingsshall be interpreted as illustrative and not in a limitingsense.

-.I- claim as my invention: refrigeration system comprising thefollowing connected to form a. closed system: boiler means forvaporizing refrigerant; a condenser for condensing refrigerant; anevaporator for evaporating refrigerant and providing a cooling effect;an absorber for absorbing refrigerant vapor; an evaporation heatexchanger operatively associated with absorber for receiving a solutionof refrigerant and absorbent material from said absorber and forproducing refrigerant vapor, at least a part of such solution beingreturned to said boiler means from said evaporation heat exchanger; andpump means having power inlet means, refrigerant inlet means anddischarge means, said pump means being so operatively associated withsaid boiler means, with said evaporation heat exchanger, and with saidcondenser that refrigerant vapor passes from said boiler means and intothe power inlet means of said pump means and from said evaporation heatexchanger and into the refrigerant inlet means of said pump means tothus discharge refrigerant vapor from the discharge means of said pumpmeans and into said condenser for condensing.

2. A refrigeration system comprising the following connected to form aclosed system: boiler means for vaporizing refrigerant; a condenser forcondensing refrigerant; and evaporator for evaporating refrigerant andproviding a cooling effect; an absorber for absorbing refrigerant vapor;an evaporation heat exchanger having a first compartment and a secondcompartment disposed in heat transfer relationship with the firstcompartment, said evaporation heat exchanger being operativelyassociated with said absorber and with said condenser so that a solutionof refrigerant and absorbent material passes from said absorber into thefirst compartment of said evaporation heat exchanger, at least a portionof such solution within the first compartment of said evaporation heatexchanger being returned to said boiler means, and so that condensedrefrigerant passes from said condenser into the second compartment ofsaid evaporation heat exchanger, said evaporation heat exchanger alsobeing operatively associated with said evaporator so that a portion ofthe refrigerant evaporated within said evaporator passes into the firstcompartment of said evaporation heat exchanger and is absorbed by theabsorbent material disposed therewithin; and pump means having powerinlet means, refrigerant inlet means and discharge means, the powerinlet means of said pump means being operatively associated with saidboiler means for receiving refrigerant vapor from said boiler means, therefrigerant inlet means of said pump means being operatively associatedwith the second compartment of said evaporation heat exchanger so as todraw refrigerant vapor therefrom and thus reduce the pressure withinsuch second compartment and thereby effect an evaporation of at least aportion of the condensed refrigerant within such second compartment andthus reduce the temperature of the solution of refrigerant and absorbentmaterial disposed within the first compartment of said evaporation heatexchanger, and the discharge means of said pump means being operativelyassociated with said condenser to discharge refrigerant vapor into saidcondenser for condensing. 1

3. The refrigeration system in accordance with claim 2 in which saidpump means is an ejector having powcr inlet means, refrigerant inletmeans and discharge means.

4. A refrigeration system for using at least a two componentrefrigerant, one component being more volatile than the other component,and comprising the following connected to form a closed system; boilermeans for vaporizing refrigerant; a condenser for condensingrefrigerant; an evaporator for evaporating refrigerant and providing acooling effect; an absorber operatively associated with said evaporatorfor receiving refrigerant vapor from said evaporator; an evaporationheat exchanger having a first compartment and a second compartmentdisposed in heat transfer relationship with the first compartment, saidevaporation heat exchanger being so operatively as sociated with saidabsorber and with said condenser that a solution of refrigerant andabsorbent material passes from said absorber into the first compartmentof said evaporation heat exchanger, at least a portion of such solutionwithin the first compartment of said evaporation heat exchanger beingreturned to said boiler means, and that a portion of the refrigerantvapor received from said evaporator passes from said absorber into thefirst compartment of said evaporation heat exchanger with proportionallymore of the less volatile component of refrigerant being absorbed insaid absorber than in absorbent material disposed within the firstcompartment of said evaporation heat exchanger, and that condensed rfrigerant flows from said condenser into the second compartment of saidevaporation heat exchanger; and pump means having power inlet means,refrigerant inlet means and discharge means, the power inlet means ofsaid pump means being operatively associated with said boiler means forreceiving refrigerant vapor from said boiler means, the refrigerantinlet means of said pump means being operatively associated with thesecond compartment of said evaporation heat exchanger so as to drawrefrigerant vapor therefrom and thus reduce the pressure within suchsecond compartment and thereby effect an evaporation of at least aportion of the condensed refrig rant within such second compartment andthus reduce the temperature of the solution of refrigerant and absorbentmaterial disposed within the first compartment of said evaporation heatexchanger, and the discharge means of said pump means being operativelyassociated with said condenser to discharge refrigerant vapor into saidcondenser for condensing.

5. A refrigeration system comprising the following connected to form aclosed system: boiler means for vaporizing refrigerant; a condenser forcondensing refrigerant; an evaporator for evaporating refrigerant andproviding a cooling effect; an absorber for absorbing refrigerant vapor;an evaporation heat exchanger for receiving a rich solution ofrefrigerant and absorbent material from said absorber and for passing aweak solution of refrigerant and absorbent material, flowing from saidboiler means to said absorber, in heat exchange relationship with suchreceived rich solution of refrigerant and absorbent material so as toeffect a separation of refrigerant from such received rich solution ofrefrigerant and absorbent material by evaporation thus producingrefrigerant vapor and leaving a residue of liquid; means for effecting aflow of at least part of such liquid residue to said boiler means; andpump means having power inlet means, refrigerant inlet means anddischarge means, the power inlet means of said pump means beingoperatively associated with said boiler means for receiving refrigerantvapor from said boiler means, the refrigerant inlet m ans of said pumpmeans being operatively associated with said evaporation heat exchangerfor pumping refrigerant vapor from said evaporation heat exchanger intothe refrigerant inlet means of said pump means, and the discharge meansof said pump means being operatively associated with said condenser todischarge refrigerant vapor into said condenser for condensing.

6. The refrigeration system in accordance with claim 5 in which saidpump means is an ejector having a power 17 inlet means, a refrigerantinlet means and discharge means.

7. The refrigeration system in accordance with claim 5 in which aprecooler is interconnected between said condenser and said evaporatorand with the refrigerant inlet means of said pump means so thatcondensed refrigerant flows from said condenser into said precooler andsaid pump means reduces the pressure within said precooler so that aportion of the condens d refrigerant within said precooler evaporatesthus cooling other associated condensed refrigerant within saidprecooler before such associa'ted'condensed refrigerant flows into saidevaporator.

8. The combination comprising, an evaporator for evaporating refrigerantand providing a cooling effect; a condenser for condensing refrigerant;a precooler, said precooler being operatively associated with saidcondenser for receiving condensed refrigerant from said condenser; andan ejector pump for reducing the pressure within said precooler tothereby evaporate a portion 0 the condensed refrigerant disposed withinsaid precoole to thus cool other associated condensed refrigerant Withilsaid precooler and for withdrawing evaporated refrigeran from saidprecooler, said precooler being operatively as sociated with saidevaporator so that cooled condenser refrigerant disposed within saidprecooler flows into Sait evaporator for evaporation.

References Cited UNITED STATES PATENTS 1,761,762 6/1930 Whitney 625011,887,957 11/1932 Altenkirch 62483 X1 1,949,732 3/1934 Whitney 62500 XI2,446,988 8/1948 Flukes 62-481 MEYER PERLIN, Primary Examiner.

U.S. DEPARTMENT OF COMMERCE PATENT OFFICE Washington, 0.6. 20231 UNITEDSTATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,402,570September 24, 1968 Ralph C. Schlichtig It is certified that errorappears in the above identified patent and that said Letters Patent arehereby corrected as shown below:

Column 15, line 18, before "absorber" insert said (SEAL) Attest:

Edward M. Fletcher, Jr.

Attesting Officer Commissioner of Patents WILLIAM E. SCHUYLER, JR.

